Fan

ABSTRACT

Fan includes a hub, a mounting ring encircling the hub, a plurality of connection poles rotatably connected to the mounting ring, and a plurality of blades fastened to the connection poles. A center of lift of each blade is located between a lower end of the blade and the connection pole fastened to the blade.

FIELD

The present disclosure relates to a fan.

BACKGROUND

In a computer, a plurality of fans is configured to dissipate heat for electronic components. The angle of attack of blades of the fans is constant, when the fans work in a high speed, turbulent flow emerges.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an exploded, isometric view of an exemplary embodiment of a fan, wherein the fan comprises a hub, a resilient member, and a transmission ring.

FIG. 2 is similar to FIG. 1, but viewed from another perspective.

FIG. 3 is an assembled, isometric view of the hub and the resilient member of FIG. 1.

FIG. 4 is an assembled view of the resilient member and the transmission ring of FIG. 1.

FIG. 5 is an assembled, isometric view of FIG. 1.

FIG. 6 is a side elevational view of FIG. 5.

DETAILED DESCRIPTION

The disclosure, including the accompanying drawings, is illustrated by way of example and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.”

FIGS. 1 and 2 illustrate an exemplary embodiment of a fan. The fan comprises a hub 10, a resilient member 20, a transmission ring 30, a stop ring 40, a mounting ring 50, a plurality of connection poles 60, and a plurality of blades 80.

The hub 10 comprises a columnar main body 12 and a circular end plate 13 formed on a first end of the main body 12. A plurality of fastening blocks 132 extends from a side of the end plate 13 facing the main body 12, and surrounds the main body 12. A plurality of hooks 14 is formed on a second end of the main body 12.

FIG. 3 illustrates that the resilient member 20 is substantially annular. The resilient member 20 comprises a plurality of C-shaped first connection portions 22 in a front side of the resilient member 20 and a plurality of C-shaped second connection portions 23 in a rear side of the resilient member 20. Each first connection portion 22 is connected between two neighbor second connection portions 23. The first connection portions 22 of the resilient member 20 are fastened to the fastening blocks 132 of the end plate 13, respectively.

Referring to FIGS. 1-2 and 4-5, the transmission ring 30 is annular. An annular spline 32 is attached to a front end of the transmission ring 30. An annular receiving slot 33 is defined in a rear end of the transmission ring 30. A plurality of abutting blocks 332 is formed in the receiving slot 33. The transmission ring 30 rotatably encircles the main body 12. The rear end of the transmission ring 30 abuts against the end plate 13. The fastening blocks 132 and the resilient member 20 are received in the receiving slot 33. The second connection portions 23 of the resilient member 20 are fastened to the abutting blocks 332 of the transmission ring 30, respectively.

The stop ring 40 is annular, and encircles the main body 12. An annular spline 42 is attached to a rear end of the stop ring 40. A plurality of hooking slots 43 is defined in a front end of the stop ring 40. The hooks 14 of the hub 10 engage in the hooking slots 43.

The mounting ring 50 is annular, and encircles the main body 12. The mounting ring 50 is sandwiched between the transmission ring 30 and the stop ring 40. A plurality of accommodating slots 52 is defined in an inner side of the mounting ring 50. A plurality of protrusions 53 extends from an outer side of the mounting ring 50. The protrusions 53 are aligned with the accommodating slots 52, respectively. Each protrusion 53 axially defines a through hole 532 communicating with the corresponding accommodating slots 52.

Each connection pole 60 comprises a gear 61 formed on a first end of the connection pole 60 and a pair of resilient latches 63 formed on a second end of the connection pole 60. The connection poles 60 rotatably extend through the through holes 532. The second ends of the connection poles 60 extend out of the protrusions 53. The gears 61 of the connection poles 60 are received in the accommodating slots 52. The gears 61 mesh with the spline 32 and the spline 42.

Referring to FIGS. 1 and 3-4, a fastening portion 821 extends from a lower surface 82 of each blade 80. The fastening portion 821 defines a through hole 823 and two opposite latching slots 824 communicating with the through hole 823. The second ends of the connection poles 60 extend through the through holes 823 of the blades 80. The latches 63 of each connection pole 60 engage in the latching slots 824 of the corresponding blade 80. The fastening portions 821 abut against the protrusions 53, to allow each blade 80 to be rotatably connected to the mounting ring 50 about a center axis 65 of the corresponding connection pole 60. The center of lift O of each blade 80 is located between a lower end 83 of the blade 80 and the connection pole 60 fastened to the blade 80.

The fan further comprises a motor received in the hub 10. When the fan works, the motor drives the hub 10 rotating about a center axis 100 of the hub 10. The blades 80 rotate about the center axis 100 of the hub 10.

Referring to FIGS. 5 and 6, when the rotational speed of the fan is increased and is higher than a predetermined speed, the lift of the blades 80 increases, to allow the blades 80 to rotate clockwise about the center axes 65. The angle of attack a of each blade 80 decreases, so that the efficiency of the fan increases. The connection poles 60 rotate clockwise, to make the gears 61 rotate clockwise. The transmission ring 30 rotates clockwise relative to the hub 10. The abutting blocks 332 press the second connection portions 23, to deform the resilient member 20. The stop ring 40 is hooked by the hooks 14, such that the stop ring 40 cannot rotate relative to the hub 10. The mounting ring 50 rotates clockwise relative to the hub 10, to keep the gears 61 meshing with the spline 42.

When the rotational speed of the fan is decreased, the lift of the blades 80 decreases. The resilient member 20 is restored to allow the transmission ring 30 to rotate counter-clockwise relative to the hub 10. The connection poles 60 rotate counter-clockwise about the center axes 65. The blades 80 rotate counter-clockwise about the center axes 65. The angle of attack a of each blade 80 increases, so that the noise of the fan is reduced. To make the gears 61 mesh with the spline 42, the mounting ring 50 rotates counter-clockwise relative to the hub 10.

Even though numerous characteristics and advantages of the embodiments have been set forth in the foregoing description, together with details of the structure and the functions of the embodiments, the disclosure is illustrative only, and changes may be made in details, especially in the matters of shape, size, and arrangement of parts within the principles of the embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

What is claimed is:
 1. A fan, comprising: a hub; a mounting ring encircling the hub; a plurality of connection poles rotatably connected to the mounting ring; and a plurality of blades fastened to the connection poles, a center of lift of each blade located between a lower end of the blade and the connection pole fastened to the blade.
 2. The fan of claim 1, further comprising a stop ring, the hub comprises a columnar main body and an end plate formed on a first end of the main body, wherein the mounting ring and the stop ring encircle the main body.
 3. The fan of claim 2, wherein a plurality of hooking slots is defined in an end of the stop ring away from the end plate, and a plurality of hooks is formed on a second end of the main body and engages in the hooking slots.
 4. The fan of claim 3, further comprising a transmission ring encircling the main body, wherein a gear is formed on an end of each connection pole away from the corresponding blade, the mounting ring is sandwiched between the stop ring and the transmission ring, each of the transmission ring and the stop ring comprises an annular spline for meshing with the gears.
 5. The fan of claim 4, further comprising a resilient member encircling the main body, wherein a plurality of fastening blocks extends from a side of the end plate facing the main body, a receiving slot is defined in an end of the transmission ring facing the end plate, a plurality of abutting blocks is formed in the receiving slot, the resilient member comprises a plurality of first connection portions fastened to the fastening blocks and, a plurality of second connection portions fastened to the abutting blocks.
 6. The fan of claim 5, wherein the first connection portions and the second connection portions are substantially C-shaped, each first connection portion is connected between two neighbor second connection portions.
 7. The fan of claim 4, wherein a fastening portion is formed on a lower surface of each blade, the connection poles are fastened to the fastening portions.
 8. The fan of claim 7, wherein each fastening portion defines a first through hole and a pair of latching slots communicating with the first through hole, each connection pole extends through the corresponding first through hole and comprises a pair of latches for engaging in the latching slots.
 9. The fan of claim 8, wherein a plurality of protrusions extends from an outer side of the mounting ring, each protrusion axially defines a second through hole, the connection poles extend through the second through holes, the fastening portions abut against the protrusions.
 10. The fan of claim 9, wherein a plurality of accommodating slots is defined in an inner side of the mounting ring and is communicated with the second through holes, the gears are received in the accommodating slots. 